X Corp, formerly known as Twitter, was sued in federal court in Florida on Monday by a legal-marketing company that claims the social media giant’s new name infringes its trademark incorporating the letter “X.”

The lawsuit by X Social Media claims that X Corp, which owner Elon Musk began rebranding to X from Twitter in July, was likely to cause consumer confusion.

The case appears to be the first of what could be numerous trademark disputes with Musk’s company over the letter “X,” which is commonly used in tech branding.

“X” is included in hundreds of federal trademarks owned by companies including Microsoft and Meta Platforms. X Corp applied for its own US trademarks covering the letter last month.

X Corp did not immediately respond to a request for comment on the complaint. X Social Media declined to comment.

Windermere, Florida-based X Social Media is an ad agency focused on mass-tort litigation. Its website says that Jacob and Roseanna Malherbe founded the agency in 2015 to connect Florida panhandle residents with attorneys in the wake of the Deepwater Horizon oil spill in the Gulf of Mexico.

The lawsuit said the agency has used the “X Social Media” name since 2016 and owns a federal trademark covering it. It said it has invested more than $400 million in Facebook advertising to reach potential clients.

The company said Twitter’s rebrand has already confused customers and caused it to lose revenue.

“In a short time, X Corp has wielded its social media clout, marketing resources, and overall national notoriety to dominate consumer perception of its ‘X’ mark,” the lawsuit said.

X Social Media asked the court to force Musk’s company to stop using the “X” name and requested an unspecified amount of money damages.